Stabilized halogen-containing resins



Patented Feb. 16, 1954 STABILIZED HALOGEN-CONTAINING RESINS Joseph R. Darby, Webster Groves, Mm, assignor to Monsanto Chemical Company, St. Louis, Mo.,

a corporation of Delaware No Drawing. Application December 21, 1951, Serial No. 262,900

16 Claims. I

This invention relates to a method of improving the stability of halogen-containing resin compositions and the stabilized compositions obtained thereby.

Halogen-containing resins ordinarily undergo discoloration and deterioration on exposure to elevated temperatures such as those employed in molding and processing operations. Various substances have been incorporated in such resins in order to prevent discoloration and deterioration but not always with fully satisfactory results.

In accordance with this invention it has been found that resins obtained from the polymerization of monomers which include or comprise a vinyl halide may be heat stabilized by incorporating therein a mixture of a zinc salt, a calcium chelate derivative of a 1,3-dicarbonylic compound capable of keto-enol tautomerism, and an organic compound containing a Composition I A i B o D Polyvinyl chloride "parts" 100 100 100 100 2-Ethylhexyl diphenyl phosphate. do 45 45 45 40 Zinc stearate d 0. 5 0. 5 0. 5 Calcium Ethylacetoacetate do 2 2 2 Butyl Glycidyl Phthalate .d

are prepared by mixing polyvinyl chloride with the respective ingredients in amounts set forth above on diiferential speed rolls at a roll temperature of 160 C. to form a homogeneous composition which is removed from the rolls in the form of crude sheets. From the crude sheets ther are molded finished sheets which are about 0.040 inch in thickness employing a molding cycle of three minutes at 160 C.

The heat stability values set forth below are obtained by heating the molded sheets at 160 C. Initially the sheets of compositions A, B, C and D are substantially colorless.

Table I Color after Heating at 160 C. for Composition 40 minutes minutes A Reddish Brown Black.

. Black Do. Slight Yellow Yellow. Substantially Colorless- Very Slight Yellow.

As further illustrative of this invention, compositions comprising respectively are prepared by mixing the copolymer of parts vinyl chloride and 5 parts vinyl acetat with the respective ingredients in amounts set forth above on diiierential speed rolls at a roll temperature of C. to form a homogeneous composition which is removed from the rolls in th form of crude sheets. From the crude sheets there are molded finished sheets which are about 0.040 inch in thickness employing a molding cycle of three minutes at 160 C.

The heat stability values set forth below are obtained by heating the molded sheets at 160 C. Initially the sheets of compositions E, F, G and H are substantially colorless.

Results similar to those obtained from compositions D and H are obtained on substituting zinc octoate, zinc laurate, and zinc oleate, respectively,

3 in the same amounts for the zinc stearate in said examples.

Compositions having similarly improved stability are prepared by replacing the epoxy compound of compositions D and H, that is, butyl glycidyl phthalate, with the same amount of, respectively, cyclohexyl-9,10-epoxyoctadecanoate, methyl-9,- 10-epoxyoctadecanoate, glycidyl laurate, 2-ethylhexyl glycidyl adipate, 1,2-epoxytetradecane, and 1,2-epoxy-3(Z-naphthoxy) propane.

Employing in compositions D and H, respectively, instead of calcium ethylacetoacetate an equal weight of calcium Z-ethylhexylacetoacetate similarly improved results are obtained.

As further illustrative of this invention are the following:

Example I A mixture of 100 parts of a copolymer of 90 parts vinyl chloride and 10 parts diethyl maleate, 50 parts of 2-ethylhexyl dicresyl phosphate, 0.3 part zinc stearate, 2 parts calcium phenylacetoacetate, and 3 parts methyl-9,10-epoxyoctadecanoate is processed into homogeneous molded sheets in the usual manner. Ihe'resultant product exhibits a heat stability comparable to that of composition D.

Example III A plasticized composition containing 100 parts polyvinyl chloride and 40 parts dodecyl diphenyl phosphate is stabilized by incorporating therein a mixture of 0.2 part zinc octate, 7 parts calcium ethylacetoacetate and 6 parts butyl glycidyl phthalate. The resulting composition possesses improved heat stability characteristics as compared with a plasticized composition containing 100 partspolyvinyl chloride, 50 parts dodecyl diphenyl phosphate, 0.2 part zinc octate and 7 parts calcium ethylacetoacetate.

Example IV .A plasticized composition containing. 100 parts polyvinyl chloride and 40 parts dioctyl phthalate is stabilized by incorporating therein a mixture of 0.2 part zinc octate, 7 parts calcium ethylacetoacetate and '6 partsglycidyl butyl phthalate. The resulting composition possesses improved heat stability characteristics as compared with a plasticized composition containing 100 parts polyvinyl chloride, 50 parts dioctyl phthalate, 0.2 part zinc octate and Iparts calcium ethyletqa te- Example V A mixtureof loo"partspoiyvi'n l "chlor'idef35 parts cyclohexyl-9,lO-epoxyo'ctade'canoate, 0.2 part zinc oleate and parts calcium ethylacetoacetate is processed into homogeneous sheets in the usual manner. possesses improved heat stability characteristics as compared with a similarly prepared composition;containing 100 parts polyvinyl chloride, 0'.2.

The resulting composition chloro butadienes, etc.

parts zinc oleate and 40 parts cyclohexyl-9,10- epoxyoctadecanoate.

Example VI A mixture of parts polyvinyl chloride, 35 parts butyl glycidyl phthalate, 0.2 part zinc oleate and 5 parts calcium ethylacetoacetate is processed into homogeneous sheets in the usual man ner. The resulting composition possesses improved. heat stability characteristics as compared with a similarly prepared composition containing 100 parts polyvinyl ChloridefOlZ part zinc oleate and 40 parts butyl glycidyl phthalate.

indicated above, it is found that surprisingly' eftectivestabilizing results are obtained according to this invention with halogen-containingresins generally, numerous examples of which are wellknowntoithose skilled in the art. Thus,

there may be. employed resins made from such vinylidene compounds as vinyl chloride, vinylidene chloride,'vinylchloracetate, chloro styrenes,

Such vinylidene compounds-may be polymerized singly or in a mixture with these or other halogen-containing vinylidene compounds or with vinylidene compounds free from halogen. 'Amongthe unsaturated materialsfree from halogen which may be copolymerized with halogen-containing vinylidene compounds are vinyl esters of carboxylic acids, for example, vmyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate; esters of unsaturated acids, for examp1e,'alkyl acrylates, such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, allyl acrylate and the corresponding esters of methacrylic acid; vinyl aromatic compounds, for example, styrene, para-ethyl styrene, divinyl benzene, vinyl naphthalene, alpha-methyl styrene; dienes, such as butadiene, unsaturated amides, such as acrylic acid amide, acrylic acid anilide, unsaturated nitriles, such as acrylic acid nitrile; estersof mp-unsaturated carboxylic acids, for example, the methyl, ethyl, propyl, butyl, amyl, hexyl, 'heptyl, octyl, allyl, methallyl, and phen'yl esters of maleic; crotonic, itaconic, iumaric acids and the like. The class of copolymers in which a,predominant portion, i. e., more than 50% by weight, of the copolymer is made from a halogen-containing vinylidene compound such as vinyl chloride representsa pre-- ferred class of polymers to betreated according to. the invention.

Among the. preierredembodiments of this .in-

chlorinated polyvinyl acetate, chlorinated pOlystyrene, chlorinated polyvinyl chloride, chlorinated natural and :synthetic-rubbers, rubber hydrochloridc, etc.

Thestabilizer mixture of this invention is also effective in halogen containing' resins containing halogens other than chlorine, e. "g, -bromine, fiuorineiand iodine.

The halogen-containing resins may contain a varying proportion of halogen depending upon the nature of the resin andiitscontemplated-use.

However, as indicated above, vinyl chloride polymers in which the proportion of vinyl chloride units amounts to 50% or more of the total monomer used in making the polymeric product represents a preferred class of polymers to be stabilized according to this invention.

The amounts of the components of the stabilizer combination of this invention may be substantially varied and still result in surprising improvement in stability of the halogen containing resin. Usually at least one part by weight of the calcium compound is used in stabilizing 100 parts by weight of a halogen containing resin and generally from 2 to 10 parts by Weight are preferred. The use of less than one part by Weight is effective to a considerable degree and amounts larger than 10 parts may be used although further improvement in stability of the resulting compositions is not in direct proportion to the amount used.

Usually the amount of the zinc salt is smaller than that of the calcium compound. Extremely small amounts of the zinc salt have a noticeable efiect on the stability but usually at least 005 part by weight for every 100 parts by weight of halogen-containing resin is employed and preferably from 0.1 part to 0.5 part. Amounts larger than 0.5 part may be employed but generally speaking, it is not advantageous to incorporate more than 1-2 parts of the zinc salt.

Usually at least 1 part of the epoxy compound is used in stabilizing 100 parts of a halogen-containing resin for most uses and generally, at least 5 parts of the epoxy compound are preferred, although smaller amounts are efiective to a considerable degree. Much larger amounts may be used, c. g., 50-100 parts, and serve to lengthen the useful life of the halogen-containing resins although not in direct proportion to the amount used. However, in some cases the epoxy compound may serve both as a plasticizer and an element of the stabilizer mixture and in such cases it may be worth while to incorporate such larger amounts. In general the total amount of zinc salt and calcium compound is smaller than that of the epoxy compound.

The epoxy compounds used in the stabilizer mixture of this invention comprise organic compounds generally containing one or more groups. Various substituted and unsubstituted aliphatic, aromatic, alicyclic and heterocyclic groups may be attached to said epoxygroups. Generally, however, the epoxy compounds which are employed should have a boiling point at atmospheric pressure of at least 150 6.; otherwise the stabilizing efiect is likely to be relatively transitory due to evaporation of the epoxy compound and preferably the epoxy compounds should have a boiling point of at least 200 C. at atmospheric pressure. Illustrative examples of epoxy compounds which may be used according to the invention are 1,2-epoxytetradecane, 1,2- epoxyoctadecane and other derivatives of long chain alkanes, for example, alkanes havin -24 carbon atoms having a group; epoxy esters containing a long carbon chain such as glycidyl laurate, methyl 9,10-

epoxyoctadecanoate, diethylene glycol di-9,10--

epoxyoctadecanoate, 9,10-epoxy octadecanyl acetate, 9,10-epoxyoctadecanyl octadecanoate, esters of polycarboxylic acids and alcohols containing a group such as di-2-ethyl hexyl epoxy succinate,

butyl glycidyl phthalate, diglycidyl phthalate." propylene glycol diglycidyl phthalate, diethylene glycol diglycidyl maleate, 2-ethyl hexyl glycidyladipate, hexyl glycidyl sebacate and other esters: of these and other poly carboxylic acids containing at least a methyl glycidol, beta-ethyl glycidol, beta-hydroxy methyl glycidol, di-isob-utenyl dioxide; epoxidized others such as alkyl glycidol ethers in which the alkyl group contains 1-5 carbon atoms, e. g.,

methyl, ethyl, propyl, butyl, amyl glycidyl ethers; glycidyl ethers containing unsaturatedgroups such as vinyl, allyl and methyl allyl glycidyl ethers. phenyl glycidyl ether, tolyl glycidyl ethers, naphthyl glycidyl ethers, cycle-- pentyl glycidyl ether, cyclohexyl glycidyl ether,

etc. Other illustrative epoxy compounds include cyclohexene oxide, l-(Z-phenylphenoxy) propylene oxide-2,3, 1-(2-phenyl-cyclohexanoxy) propylene oxide-2,3, l-(cyclohexanoxy) propylene oxide-2,3, 1-(2-cyclohexylphenoxy) propylene oxide-2,3, l-( l-tertiary butyl phenoxy) propylene oxide-2,3, styrene oxides such as styrene oxide,-

para-ethyl styrene oxide, dimethyl-styrene oxide,'

ortho-methoxy styrene oxide, 4-(2,3-epoxy-propoxy) acetyl phenone, the corresponding benzophenone epoxide, 4,4'-di(2,3-epoxy-propoxy) benzophenone, mesityl oxide epoxide, epoxy alkyl and epoxy cycloalkyl amides such as 2-ethyl-3-propyl' glycidamide, 2,3-dipropylglycidainide; aryloxyalkene oxides such as phenoxy propene oxide,- para-tertiary amyl and para-secondary amyl phenoxy propene oxides.

According to one embodiment of this invention the epoxy compounds are epoxy ethers such as the glycidyl ethers of such polyhydric alcohols as glycerin, diglycerol, erythritol, pentaglycerol, pentaerythritol, mannitol, sorbitol, polyallyl alcohol, polyvinyl alcohol, ethylene glycol,'propylene glycol, butylene glycol, etc.

One of the preferred classes of epoxy com-\ pounds comprises high molecular weight or resinous epoxy compounds, for example, those made by reacting polyhydric phenols with epichlor-' hydrin in various ratios in alkaline solution.

Among the polyhydric phenols which may be used 4 in preparing such glycidyl ethers are mono nuclear phenols like resorcinol, catechol, hydro-' quinone, etc., or polynuclear phenols like bis-(4 hydroxyphenyl)-2,2-propane (bis-phenol), 4,4- dihydroxy benzophenone, bis- (4-hydroxyphenyl) 1,1-ethane, bis- (4 hydroxyphenyl) -1,1 ethane, bis- (4-hydroxyphenyl) -1,1-isobutane, bis-.(d-hybis (4 hydroxy-x droxyphenyl) 2,2 butane,

tertiary'butyl phenyl-) --2,'2 -propane, bis-(Z dihydroxynaphthylimethane, 1,5 -dihydroxynaphthalene, phloroglucinol, l,4-'-dihydroxy naphthalene, 9,10-hydroxy anthracene, 1,3,6-trihydroxy naphthalene, 4,4-dihydroxy diphenyl, 2,2-bis- (4-hydroxy phenyl) propane and 1,4-bis-(4-hydroxy phenyl) cyclohexane, etc. Such henols may be: reacted witheepichlorhydrin. in the presencehof an inorganic alkaline material to form the epoxy compounds, which, depending upon the conditions. of the .reaction, may be either monomeric or. polymeric materials. Examples.v of such epoxy compounds include 1,4-diglycidol.

epoxy benzenes and 2,2-bis(4-glycidol oxyphenyl) propanes. 1

Other compounds containing a group whichmay be .usedinaccordance withl'this invention .include those made .by reacting alkyl sulfony1 chlorides with glycidol in the presence ofammonia wherein the alkyl, group contains up to 20.01. more carbon. atoms, e. g.,

etc.

Various :zinc saltsmaybe employed inthe stabilizer combination of this invention, for example, zinc. salts of organic acids, as well as zinc salts of. inorganic acids; which give a neutral or alkaline reactionin an aqueous medium, i. e., zinc salts-of weak inorganic acids. Examples of zinc salts oforganic acids which .may be employed are those madefrom such acids as. saturated aliphatic acids, e. e., ethanoic, propanoic, butanoic,

pentanoic, hexanoic, .heptanoic, octanoic, nonanoic, decanoic, hendecanoic, dodecanoic, tetradecanoic, hexadecanoic andoctadecanoic; monoolefinic-unsaturated aliphatic acids such as propenoic acid, 2-butenoic acid,.2-methyl-2 -propenoic acid, 3-butenoic acid, 2-pentenoic acid. 4-pentenoie acid, 2-methyl-2-butenoic acid, .2- hexenoic acid, '7-hexadecenoic acid, .IO-undecenoic acid,,l3-docosenoic acid, 3-hexenoic acid, and 9-octadecenoic acid; diolefinic-unsaturated aliphatic acids such as 2,4-pentadienoic acid,

2A- hexadienoic acid, ,3,? dimethyl-2,6-octadienoicacid, 9,12-octadecadienoic acid; triolefinicunsaturated aliphatic acidssuch as 3,7-dimethyl- 2,4,6-octatrienic. acid, 9,12,l-octadecatrienoic acid, 9,11,13-octadecatrienoic acid; substituted olefinic acids, for example, suchhydroxy olefinic acidsas 2-hydroxy-3-butenoic acid, lfi-hydroxy- 'T-hexadecenoic acid and l2-hydroxy-9-octadecenOic acid; acetylenic unsaturated aliphatic acids such as propynoic, butynoic, pentynoic, amyl' boxylic acids obtained by polymerization of -un-" 8 saturated-fatty: acids, e. g., oleicacld dimer-and linoleic acid dimer; salts of: aromatic acids, e.:g., zinc salts of phenyl-acetic, benzoic, phthalic-and salicylic acids; salts of cyclic acids, e. g'., the zinc salt of abietic acid.

The zinc salts maybe either neutral or basic salts when monocarboxylic acids are used. Mixed saltsmade from mixtures of acidsmay also be used;

.As examples of zinc salts of weak inorganic acids are zinc salts. of carbonic silicic, boric acids and the like.

Ofthe various zinc salts which may be used in the. stabilizer combination of the invention a preferredclass comprises those made from saturated monocarboxylic aliphatic acids containing at: least 10 carbon atoms, e. g., 10 to 24'carbon atoms such as those mentioned above.

The calcium chelates which are usedin the stabilizer combination of the invention are calcium chelates of derivatives of 1,3-dicarbonyl compounds capable of keto-enol tautomerism such as betadiketones, beta-ketoacids and the esters of betaretoacids.

A preferred class of such calcium compounds are the calcium chelates of ethylacetoacetate, butyl acetoacetate, 2-ethylbutyl acetoacetate,/2- ethylhexyl acetoacetate, N-octyl acetoacetate, phenylacetoacetate, benzyl acetoacetate, phenylethyl acetoacetate, tolyl acetoacetate as well as other aliphatic and aromatic esters of acetoacetic acid. However, the calcium chelate of thefree' beta-keto acids such as acetoacetic acid, etc., may be used. Examples of calcium chelates of diketones include those'made from acetyl acetone. benzyl acetone, diacetylacetone, and the like.

The stabilizer combination of this invention is of particular importance in stabilizing halogencontaining resins especially vinyl chloride polymers plasticized with phosphate esters such as the alkyl diaryl phosphates in which the alkyl group contains 6-14 carbon atoms and the aryl groups are phenyl or cresyl groups, i. e., ortho-i, metaor paracresyl groups and mixtures thereof since compositions containing such plasticizers have proved to be especially difficult to stabilize. Examples of such esters include'2-ethylhexyl'diphenyl phosphate, Z-ethylhexyl dicresyl phosphate, Z-ethylhexyl phenyl cresyl phosphate,

. hexyl diphenyl phosphate, hexyl phenyl cresyl phosphate, hexyl dicresyl phosphate, dodecyl diphenyl phosphate, 'dodecylphenyl cresyl phosphate, dodecyl dicresyl phosphate, etc. Mixtures of such esters may frequently be used advan-' tageously. The amount of the phosphate ester which is. used may be substantially varied depending upon the particular ester and upon the particular use which is contemplated for the plasticized composition. Usually howevenirom 10 to parts of the esters are used forevery 100 parts of vinyl chloride-containing,resin.

As indicated by the examples, plasticizers other thanalkyl diaryl' phosphate esters may be employed as Well as mixtures of such phosphate esters and. sucheconventionalplasticizers as dioctyl phthalate, tricresyl phosphate, butyl phthalyl butyl glycolate, etc. In the case of certain halogen-containing resins no plasticizers are required.

In addition to the stabilizer combination of the invention, other heat stabilizers and also light stabilizers may be included, if desired, examples of which are well known to those skilled in the artas Welles other'conventional additives such as other resins, lubricants, coloring materials,

' capable of keto-enol tautomerisrn.

The foregoing description is given in illustration and not in limitation of the invention as set forth in the appended claims.

What is claimed isf 1. A composition resistant to the discoloration efi'ects of heat comprising a halogen-containing resin and as a stabilizer therefor in stabilizing amounts a mixture of a zinc salt, a calcium chelate derivative of a 1,3-dicarbonylio compound capable of keto-enol tautomerism, and an epoxy compound.

2. A composition resistant to the discoloration efiects of heat comprising a chlorine-containing resin and as a stabilizer therefor a mixture containing at least 0.05 part by weight per 100 parts by weight of said resin of a zinc salt, at least 1 part by weight per 100 parts by weight of said resin of a calcium chelate derivative of a 1,3- dicarbonylic compound capable of keto-cnol tautomerism, and at least 1 part by weight per 100 parts by weight 01 said resin of an epoxy compound.

3. A composition resistant to the discoloration effects of heat comprising a halogen-containing resin and as a stabilizer therefor a mixture containing at least 0.05 part by weight per 100 parts by weight of said resin of a zinc salt, at least 1 part by weight per 100 parts by weight of said resin of calcium ethylacetoacetate, and at least 1 part by weight per 100 parts by weight of said resin of an epoxy compound.

4. A composition resistant to the discoloration efiects of heat comprising a halogen-containing resin and as a stabilizer therefor a mixture containing from 0.1 to 0.5 parts by weight of a zinc salt of an organic acid, from 2 to 10 parts by weight of a calcium chelate derivative of a 1,3- dicarbonylic compound capable of keto-enol tautomerism, and from 5 to 100 parts by weight of an epoxy compound, said weight proportions being based upon 100 parts by weight of said resin polymer.

5. A composition resistant to the discoloration effects of heat comprising a chlorine-containing resin and as a stabilizer therefor a mixture containing from 0.1 to 0.5 parts by weight of a zinc salt of an organic acid, from 2 to parts by Weight of a calcium chelate derivative of a 1,3- dicarbonylic compound capable of keto-enol tautomerism, and from 5 to 100 parts by weight of an epoxy compound, said weight proportions being based upon 100 parts by weight of said resin polymer.

6. A composition resistant to the discoloration effects of heat comprising a halogen-containing resin and as a stabilizer therefor a mixture containing from 0.1 to 0.5 parts by weight of a zinc salt of a monocarboxylic saturated aliphatic acid containing at least 10 carbon atoms, from 2 to 10 parts by weight of a calcium chelate derivative of a 1,3-dioarbonylic compound capable of keto-enol tautomerism, and from 5 to 100 parts by Weight of an epoxy compound, said weight proportions being based upon 100 parts by weight of said resin polymer.

7. A composition resistant to the discoloration eifects of heat comprising a vinyl chloride polymer and as a stabilizer therefor a mixture containing from 0.1 to 0.5 parts by weight of a zinc salt of an organic acid, from 2 to 10 parts by weight of a calcium chelate derivative of a 1,3- dicarbonylic compound capable of keto-enol tautomerism, and from 5 to 100 parts by weight of an epoxy compound, said weight proportions being based upon 100 parts by weight of said resin polymer.

8. A composition resistant to the discoloration eiiects of heat comprising polyvinyl chloride and as a stabilizer therefor a mixture containing from 0.1 to 0.5 parts by weight of a zinc salt of an organic acid, from 2 to 10 parts by Weight of a calcium chelate derivative of a 1,3-dicarbonylic compound capable of keto-enol tautomerism, and from 5 to parts by weight of an epoxy compound, said weight proportions being based upon 100 parts by weight of said resin polymer.

' 9. A composition resistant to the discoloration effects of heat comprising a vinyl chloride-vinyl acetate eopolymer and as a stabilizer therefor a mixture containing from 0.1 to 0.5 parts by weight of a zinc salt or" an organic acid, from 2 to 10 parts by weight of a calcium chelate derivative of a 1,3-dicarbonylic compound capable of ketcenol tautomerism, and from 5 to 100 parts by weight of an epoxy compound, said weight proportions being based upon 100 parts by weight of said resin polymer.

10. A composition resistant to the discoloration eifects of heat comprising a vinyl chloride-diethyl maleate copolymer and as a stabilizer therefor a mixture containing from 0.1 to 0.5 parts by weight of a zinc salt of an organic acid, from 2 to 10 parts by weight of a calcium chelate derivative of a 1,3-dicarbonylic compound capable of keto-enol tautomerism, and from 5 to 100 parts by weight of an epoxy compound, said weight proportions being based upon 100 parts by weight of said resin polymer.

11. A heat resistant composition comprising a vinyl chloride polymer and as a stabilizer therefor a mixture containing from 0.1 to 0.5 parts by Weight of zinc stearate, from 2 to 10 parts by weight of calcium ethylacetoacetate and from 5 to 100 parts by weight of an epoxy compound having a boiling point of at least C., said weight proportions being based upon 100 parts by weight of said polymer.

12. A heat resistant composition comprising a vinyl chloride polymer and as a stabilizer therefor a mixture containing from 0.1 to 0.5 parts by weight of zinc stearate, from 2 to 10 parts by weight of calcium ethylacetoacetate and from 5 to 100 parts by weight of an epoxy compound having a boiling point of at least 200 0., said weight proportions being based upon 100 parts by weight of said polymer.

13. A heat resistant composition comprising 100 parts by weight of a vinyl chloride polymer, from 10 to 100 parts by weight of a phosphate ester plasticizer and as a stabilizer therefor a mixture containing from 0.1 to 0.5 parts by weight of zinc stearate, from 2 to 10 parts by weight of calcium ethylacetoacetate and from 5 to 100 parts by weight of an epoxy compound having a boiling point of at least 200 C.

14. A heat resistant composition comprising 100 parts by weight of a vinyl chloride polymer, from 10 to 100 parts by weight of an alkyl diaryl phosphate in which the alkyl group contains 6 to 14 carbon atoms and the aryl radical is selected from the group consisting of phenyl and .11 cresyl .radicalsand as astabilizer therefor a mixture containingjrfrom 10.1 to 0.5 parts by weight of. zinc stearateirom? to,I0 parts by weight of calcium ethylacetoacetate and from 5.150 100 parts vby weightof an epoxy compoun'djhavinga boiling point of at'1east'200' C.

,15. A heat IBSlStEtllt compositioncomprising 100 parts by weight ,of ,a vinyl chloride-vinyl t acetate copolymentfrom 10 to .100 parts by weight of an alkyl diaryl phosphate in which thevalkyl groupcontains 6 1201.4 carbonatoms'and the aryl radical is. selected .fromthegroup consisting of phenyl andcresyl radicals and aszag'stabilizer therefore. mixture containing from 0.1 to 0.5 parts partsby weight of calcium ethylacetoaceta'te and from 5 to1100 parts by weightof an epoxy compound jhaving a boiling point of at 1east-2001C. "16. A heat resistant composition comprising "100 parts by weight of a vinyl chloride-methyl maleate copo1ymer;from 10 to"100 parts byweight by weight of zinc stearate,'from 2 to;.10

. 2 44 of...an a1kyl.diary1 phosphate in whichtthealkyl group contains 6 to 14 carbon atoms and;.;the caryl radical is selected from thegroup-cansist- .ing of phenyl and -cresyl rafiicalsuand asza-sta- References Cited in therfile ofhthis patent UNITED .S'I'A'IEES PATENTS Number Name .Date

Y 2,307,075 Quattlebaumeet-aal. M. Jan."I5..":1'943 2,557,089 Gamrath et a1. June-19, 1951 2,564,646 Leistner :et :.a1.,.-.. .Aug. 14.11951 2,590,059 Wink1er Mar.';.18.,:1952 

1. A COMPOSITION RESISTANT TO THE DISCOLORATION EFFECTS OF HEAT COMPRISING A HALOGEN-CONTAINING RESIN AND AS A STABILIZER THEREFOR IN STABILIZING AMOUNTS A MIXTURE OF A ZINC SALT, A CALCIUM CHELATE DERIVATIVE OF A 1,3-DICARBONYLIC COMPOUND CAPABLE OF KETO-ENOL TAUTOMERISM, AND AN EPOXY COMPOUND. 